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Prepare for your math final exam with this comprehensive review covering key topics from textbooks, explorations, and class notes. Includes practice problems and common mistakes to avoid.
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What is on the test? • From book: 1.2, 1.3, 1.4, 1.7; 2.3; 3.1, 3.2, 3.3, 3.4; 4.2, 4.3; 5.2, 5.3, 5.4; 6.1, 6.2 • From Explorations: 1.1, 1.4, 1.7; 2.8, 2.9; 3.1; 3.13, 3.15, 3.19, 3.20, 4.2, 4.3, 5.8, 5.9, 5.10, 5.12, 5.13, 5.15, 5.16, 6.3, 6.5, • From Class Notes: Describe the strategies used by the students--don’t need to know the names.
Chapter 1 • A factory makes 3-legged stools and 4-legged tables. This month, the factory used 100 legs and built 3 more stools than tables. How many stools did the factory make? • 16 stools, 13 tables
Chapter 1 • Fred Flintstone always says“YABBADABBADO.” If he writes this phrase over and over, what will the 246th letter be? • D
Chapter 2 • Explain why 32 in base 5 is not the same as 32 in base 6. • 32 in base 5 means 3 fives and 2 ones, which is 17 in base 10. • 32 in base 6 means 3 sixes and 2 ones, which is 20 in base 10. So, 32 in base 5 is smaller than 32 in base 6.
Chapter 2 • Why is it wrong to say 37 in base 5? • In base 5, there are only the digits 0, 1, 2, 3, and 4. 7 in base 5 is written 12.
Chapter 2 • What error is the student making? “Three hundred fifty seven is written 300507.” • The student does not understand that the value of the digit is found in the place: 300507 is actually 3 hundred-thousands plus 5 hundreds and 7 ones. Three hundred fifty seven is written 357--3 hundreds plus 5 tens plus 7 ones.
Chapter 3 • List some common mistakes that children make in addition. • Do not line up place values. • Do not regroup properly. • Do not account for 0s as place holders.
Chapter 3 • Is this student correct? Explain. • “347 + 59: add one to each number and get 348 + 60 = 408.” • No: 347 + 59 is the same as 346 + 59 because 346 + 1 + 60 - 1 = 346 + 60 + 1 - 1, and 1 - 1 = 0. The answer is 406.
Chapter 3 • Is this student correct? • “497 - 39 = 497 - 40 - 1 = 457 - 1 = 456.” • No, the student is not correct because 497 - 39 = (497) - (40 - 1) = (497) - 40 + 1 = 458. An easier way to think about this is 499 - 39 = 460, and then subtract the 2 from 499, to get 458.
Chapter 3 • Is this student correct? • “390 - 27 is the same as 300 - 0 + 90 - 20 + 0 - 7. So, 300 + 70 + -7 = 370 + -7 = 363.” • Yes, this student is correct. This is analogous to 390 = 380 + 10 = 27; 300 - 0 + 80 - 20 + 10 - 7 = 300 + 60 + 3. Note: to avoid this negative situation, we regroup.
Chapter 3 • Multiply 39 • 12 using at least 5 different strategies. • Lattice Multiplication • Rectangular Array • Egyptian Duplation • Lightning-Cross • 39 • 10 + 39 • 2 • 40 • 12 - 1 • 12 • 30 • 10 + 9 • 10 + 30 • 2 + 9 • 2 = (30 + 9)(10 + 2)
Chapter 3 • Divide 259 ÷ 15 using at least 5 different strategies. • Scaffold • Repeated subtraction • Repeated addition • Use a benchmark • Partition (Thomas’ strategy)
Chapter 3 • Models for addition: • Put together, increase by, missing addend • Models for subtraction: • Take away, compare, missing addend • Models for multiplication: • Area, Cartesian Product, Repeated addition, measurement, missing factor • Models for division: • Partition, Repeated subtraction, missing factor
• • • • • • Chapter 4 • An odd number: • An even number:
Chapter 4 • Prime numbers: 2, 3, 5, 7, 11, 13, 17, 19, … 2 factors • ONE IS NOT PRIME. • Composite numbers: 4, 6, 8, 9, 10, 12, 14, 15, 16, 18, … at least 3 factors • Square numbers: 1, 4, 9, 16, 25, 36, 49, 64, 81, … an odd number of factors
Chapter 4 • Prime factorization: many ways to get the factorization, but only one prime factorization for any number. • Find the prime factorization of 84. • 2 • 2 • 3 • 7, or 22 • 3 • 7
Chapter 4 • Greatest Common Factor: The greatest number that can divide evenly into a set of numbers. • The GCF of 50 and 75 is 25. • You try: Find the GCF of 60, 80, and 200. • 20: 60 = 20 • 3, 80 = 20 • 4, 200 = 20 • 10.
Chapter 4 • The Least Common Multiple is the smallest number that is divisible by a set of numbers. • The LCM of 50 and 75 is 150. • You try: Find the LCM of 60, 80, and 200. • 1200: 60 • 20 = 1200, 80 • 15 = 1200, 200 • 6 = 1200.
Chapter 4 • What is the largest square that can be used to fill a 6 x 10 rectangle. • 2 x 2: You can draw it to see why. (Which is involved here, GCF or LCM?)
Chapter 5 • Fractions models:Part of a wholeRatioOperatorQuotient • Make up a real-world problem for each model above for 6/10.
Chapter 5 • Name the model for each situation of 5/6. • I have 5 sodas for 6 people--how much does each person get? • Out of 6 grades, 5 were As. • I had 36 gumballs, but I lost 6 of them. What fraction describes what is left? • In a room of students, 50 wore glasses and 10 did not wear glasses.
Chapter 5 • There are three ways to represent a fraction using a part of a whole model:part-wholediscrete,number line (measurement) • Represent 5/8 and 11/8 using each of the pictorial models above.
Chapter 5 • Errors in comparing fractions: 2/6 > 1/2 • Look at the numerators: 2 > 1 • Two pieces is more than one piece. • Look at the denominators: 6 > 2 • We need 6 to make a whole rather than 2. • There are more pieces not shaded than shaded. • If we look at what is not shaded, then there are more unshaded pieces. The pieces are smaller in sixths than in halves.
Chapter 5 • Appropriate ways to compare fractions: • Rewrite decimal equivalents. • Rewrite fractions with common denominators. • Place fractions on the number line. • Sketch parts of a whole, with the same size whole
Chapter 5 • More ways to compare fractions: • Compare to a benchmark, like 1/2 or 3/4. • Same numerators: a/b > a/(b + 1) 2/3 > 2/4 • Same denominators: (a + 1)/b > a/b 5/7 > 4/7 • Look at the part that is not shaded: 5/9 < 8/12 because 4 out of 9 parts are not shaded compared with 4 out of 12 parts not shaded.
Chapter 5 • Compare these fractions without using decimals or common denominators. • 37/81 and 51/90 • 691/4 and 791/7 • 200/213 and 199/214 • 7/19 and 14/39
Chapter 5 • Remember how to compute with fractions. Explain the error: • 2/5 + 5/8 = 7/13 • 3 4/7 + 9/14 = 3 13/14 • 2 7/8 + 5 4/8 = 7 11/8 = 8 1/8 • 5 4/6 + 5/6 = 5 9/6 = 5 1/2
Chapter 5 • Explain the error: • 3 - 4/5 = 2 4/5 • 5 - 2 1/7 = 3 6/7 • 3 7/8 - 2 1/4 = 1 6/4 = 2 1/2 • 9 1/8 - 7 3/4 = 9 2/8 - 7 6/8 = 8 12/8 - 7 6/8 = 1 4/8 = 1 1/2
Chapter 5 • Explain the error: • 3/7 • 4/9 = 7/16 • 2 1/4 • 3 1/2 = 6 1/8 • 7/12 • 4/5 = 35/48 • 4/7 • 3/5 = 20/35 • 21/35 = 420/1225 = 84/245 = 12/35
Chapter 5 • Explain the error: • 3/5 ÷ 4/5 = 4/3 • 12 1/4 ÷ 6 1/2 = 2 1/2
Chapter 5 • Decimals: • Name a fraction and a decimal that is closer to 4/9 than 5/11. • Explain what is wrong: • 3.45 ÷ .05 = 0.69
Chapter 5 • True or false? Explain. • 3.69/47 = 369/470 • 5.02/30.04 = 502/3004
Chapter 5 • Order these decimals: • 3.95, 4.977, 3.957, 4.697, 3.097 • Round 4.976 to the nearest tenth. Explain in words, or use a picture.
Chapter 6 • An employee making $24,000 was given a bonus of $1000. What percent of his salary was his bonus? • 1000/24,000 = x/100 • 100,000 = 24,000x x ≈ 4.17%
Chapter 6 • Which is faster? • 11 miles in 16 minutes or 24 miles in 39 minutes? Explain.
Chapter 6 • Ryan bought 45 cups for $3.15. “0.07! That’s a great rate!” • What rate does 0.07 represent? • Describe this situation with a different rate--and state what this different rate represents.
Chapter 6 • Which ratio is not equivalent to the others? • (a) 42 : 49 • (b) 12 : 21 • (c) 50.4 : 58.8 • (d) 294 : 357
Chapter 6 • Write each rational number as a decimal and a percent. • 3 • 4/5 • 1/11 • 2 1/3
Chapter 6 • Write each decimal as a fraction in simplest form and a percent. • 4.9 • 3.005 • 0.073
Chapter 6 • Write each percent as a fraction and a decimal. • 48% • 39.8% • 2 1/2% • 0.841%
Chapter 6 • A car travels 60 mph, and a plane travels 15 miles per minute. How far does the car travel while the plane travels 600 miles? • (Hint: you can set up one proportion, two proportions, or skip the proportions entirely!) • Answer is the car travels 40 miles--the car travels 1 miles for each 15 miles the plane travels. 1/15 = x/600.
Chapter 6 • DO NOT set up a proportion and solve: use estimation instead. • (a) Find 9% of 360. • (b) Find 5% of 297. • (c) Find 400% of 35. • (d) Find 45% of 784.
Chapter 6 • DO NOT set up a proportion and solve: use estimation instead. • (e) What percent of 80 is 39?(f) What percent of 120 is 31?(g) 27 is what percent of 36?(h) 87 is 20% of what number? • Now, go back and set up proportions to find the exact values of (a) - (h). Were you close?
Chapter 6 • Iga Tahavit has 150 mg of fools’ gold. Find the new amount if: • She loses 30%? • She increases her amount by 90%? • She decreases her amount by 40%?
Percent & Proportion Questions • In Giant World, a giant tube of toothpaste holds one gallon. If a normal tube of toothpaste holds 4.6 ounces and costs $2.49, how much should the giant tube cost? • One gallon is 128 ounces. Ounces = 4.6 = 128 Dollars $2.49 x4.6x = 128 • 2.49 About $69.29
Estimate • In Giant World, a giant tube of toothpaste holds one gallon. If a normal tube of toothpaste holds 4.6 ounces and costs $2.49, how much should the giant tube cost? • If we round, we can think: 4 ounces is about $2.50. Since we want to know how much 128 ounces is, think: 4 • 32 = 128, so $2.50 times 32 is $80. (or, $2.50 • 30 = $75)
Try this one • The admissions department currently accepts students at a 7 : 3 male/female ratio. If they have about 1000 students in the class, how many more females would they need to reduce the ratio to 2 : 1? • Currently: 7x + 3x = 1000, so x = 100; 700 males and 300 females. They want 2y + 1y = 1000, so y = 333; 666 males and 333 females. They need to accept 333 - 300 = 33 more females to achieve this ratio.
Try this one • Lee’s gross pay is $1840 per paycheck, but $370 is deducted. Her take-home pay is what percent of her gross pay? • Part = percent = 370 = xWhole 100 1840 100 • 370 • 100 = 1840x; About 20% is taken out, so about 80% for take-home pay. • Could also do: 1840 - 370 = 1470: 1470 = x 1840 100
Last one • Estimate in your head: • 16% of 450 • 10% of 450 = 45; 5% = 22.5, about 67.5 OR 10% of 450 = 45; 1% of 450 = 4.5, or about 5; 6 • 1% = 6 • 5 = 30; 30 + 45 = 75. • 123 is approximately what percent of 185? • Approximate: 120 is approximately what percent of 200; 120/200 = 60/100, so about 60%.